Lab 2 Flashcards
Analogous
when a similar character in two or more tax is not a result of a common ancestor but instead of convergent evolution (e.g. wings of an insect and wings of a bird)
Ancestral (or plesiomorphic) Character State
a character state that was seen in the early ancestors of an organism (e.g. reptiles having four legs)
Branch
a line on a phylogenetic tree that connects a node to a terminal taxon
Character
some observable features of an organism
it can be morphological, molecular, developmental, physiological, behavioural, or ecological (e.g. either presence or absence of legs)
Clade
a lineage that arose for one ancestor (a monophyletic lineage)
Cladogram/Phylogeny/Phylogenetic Tree
a tree structure that represents the evolutionary relationships within a group of organisms (three terms are interchangeably)
Convergent Evolution
occurs when similar characters evolve independently in two or more texa
Character State Reversals
occur when a derived character reverts to an ancestral condition
Derived (or apomorphic) Character State
a character state that was not seen in the early ancestors of an organism (e.g. limblessness of snakes )
a modified character state (with reference to another, ancestral, character state)
Homologous
when a character in two or more taxa can be tracked back to the character in their common ancestor, or where one character state in a taxon is derived from that in another (i.e. similarity resulting from common descent)
Homoplasy (-ies)
similarities in characters of different species resulting from convergent evolution and/or character state reversals, and not resulting from common descent
Ingroup
the group that is now being analyzed
Internode
a line on a phylogenetic tree that connects two nodes
Monophyletic Group (also called a Clade)
a phylogenetic lineage composed of two or more taxa including the common ancestral taxon and all descendants
Node
a branching point on a phylogenetic tree or cladogram that represents a speciation event in which one ancestral taxon gave rise to two distinct descendant taxa
branches above the node can be rotated without changing the relationship of the taxa